Sacroiliac Jt. Flashcards
(50 cards)
Anterior Tilt
ASIS move inferiorly and PSIS move superiorly (ASIS move anteriorly)
Creates relative flexion of hip
Increases lumbar lordosis
Posterior Tilt
PSIS move inferiorly and ASIS move superiorly (ASIS move posteriorly)
Creates relative extension of hip
Flattens lumbar lordosis
Nutation: Sacral Flexion
(Sacral Locking)
Relative anterior tilt of the base of sacrum relative to ilium
base of sacrum moves anteriorly, coccyx moves posteriorly SACRUM
posterior pelvic tilt PELVIS
Ilia move closer together
Ishial tuberosities move farther apart
Counternutation: Sacral Extension
Sacral unlocking
Relative posterior tilt of the base of the sacrum relative to the ilium
Base of sacrum moves posteriorly, coccyx moves anteriorly SACRUM
anterior pelvic tilt PELVIS
Ilia move farther apart
Ischial tuberosities move closer together
What does the Iliolumbar ligament do?
Stabilizes lumbosacral jt
Reinforces anterior aspect of jt
Basically connects everything together anteriorly
What does the Interossesous ligament do?
STRONGEST SI JT LIGAMENT
Rigidly binds sacrum and ilium
(Runs straight across/transversely to connect the sacrum and ilium)
What does the Anterior sacroiliac ligament do?
Thinner compared to other SI ligaments
Thickening of anterior jt capsule
Limits nutation
-> base of sacrum moving anteriorly
Runs from top of base of Sacrum to ilium (curves)
What does the Long posterior sacroiliac ligament do?
Limits anterior pelvic tilt (rotation) OR sacral counternutation
Runs from ilium to coccyx (prevents coccyx from going anterior)
What does the short sacroiliac ligament do?
Limits all pelvic and sacral movement
What does the Sacrotuberous and Sacrospinous ligament do?
Limit nutation and posterior innominate tilt
Provide vertical stability (resist superior translation of sacrum)
Runs from coccyx to ischial tuberosity
Walking
Reciprocal flexion and extension of LEs
- Each side of pelvis rotates out of phase with other
- Most pronounced in SAGITTAL PLANE, but also occurs in TRANSVERSE PLANE
- Intrapelvic torsions are greater with increased walking speed
What happens in Lumbar Flexion?
Innominate and Sacrum
Innominate: Anterior tilt
Sacrum: Counternutation
What happens in Lumbar Extension
Innominate and Sacrum
Innominate: Posterior tilt
Sacrum: Nutation
What happens in Lumbar Rotation
Innominate and Sacrum
Innominate
Ipsilateral side: posterior tilt
Contralateral side: anterior tilt
Sacrum
Ipsilateral side: nutation
Contralateral side: counternutation
What happens in Lumbar Side Bend
Innominate and Sacrum
Innominate
Ipsilateral side: anterior tilt
Contralateral side: posterior tilt
Sacrum
Ipsilateral side: counternutation
Contralateral side: nutation
What happens with Restricted hip flexion?
Greater flexion in lower thoracic and lumbar regions is needed to compensate
(Tight hamstrings)
What happens with Restricted lumbar mobility?
Greater hip flexion is required to compensate
(Back pain)
Phases of Extending to Upright from Flexed Position
- Initial Trunk Extension
- Hip extension, via activation of hip extensors (glut max and hamstrings) - Middle phase
- Trunk extension occurs via shared activation of hip and lumbar extensors - Muscle activity is largely decreased once LOG shifts posterior to hips
Center Edge Angles
Definite dysplasia: less than 16 degrees; prone to dislocation
Possible dysplasia: 16-25 degrees
Normal: 25-40 degrees
Excessive acetabular coverage greater than 40 degrees
What is Coxa Valga?
GREATER angle of inclination (greater than 125 degrees)
Femoral articular surface contact area w/ acetabulum DECREASES -> which DECREASES joint stability (increase jt. degeneration, instability and joint reaction force)
Vertical WBing line shifts closer to shaft of femur
-> Decreased distance between femoral head and greater trochanter DECREASES MA of hip ABDUCTORS
-> Increased force demand to counterbalance adduction during single leg stance
-> Abductors could be weakened
What is Coxa Vara?
Angle of inclination DECREASES (less than 125 degrees)
Femoral head rests deeper in acetabulum -> which improves congruence
MA of hip abductor muscles will be INCREASED
-> decreased force needed by abductors in SLS and decreased joint reaction force
Disadvantage: INCREASED bending moment along femoral head and neck
-> increased density due to increased tensile stresses
-> increase shear force along femoral neck will INCREASE FRACTURE RISK
Excessive Anteversion (Angle of Torsion)
Pathological INCREASE in angle
Angle greater than 15-20 degrees
Increased IR ROM and decreased ER ROM
Reduces hip joint stability
“In-toe” in standing or during gait to improve alignment of articular surfaces
Retroversion (Angle of Torsion)
Pathological DECREASE in angle of torsion
Angle less than 15-20 degrees
Associated with increased ER ROM and decreased IR ROM
“Out-toe” in standing to improve articular alignment